Craftsman Style Arbor

We remodeled the exterior of our house a few years ago, which included our ode to the Gamble house in the new front door and windows (the contractor did that work). The arbor was part of the architect’s design, but got sidelined. I just finished this project last weekend.

I mostly stuck to the original design, but did some enhancements, the types of things you think “this would look really great” and then it takes you an extra 20 hours. Well, maybe not you, but definitely me.

It’s funny, but there was nothing in this job much more complicated than “careful carpentry and finishing”. A lot of measuring and mockups – including a mocked-up rafter that helped me find and solve some important clearance and dimension problems, and foam core mockups of the columns. Still, it took a lot longer than I thought….but I’m super happy with the results. More details below if you are interested.

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The big beam across the top is 14 feet long, 7 1/2 inches tall and 5 1/2 inches wide. It weighs about 120 pounds. I built it up from a single piece of cedar (the center) and multiple pieces of 3/4 inch mahogany. So it’s essentially a laminate beam of cedar and mahogany, glued together with Titebond III and triple-coated in spar varnish.

The rafters are cedar, stained to match the mahogany (lots of trial and error there). I got the clearest cedar I could find, so there are no knots to immediately give away the difference in the wood. To cut the dados for a neat fit on the beam, I lined up and clamped all 9 rafters side by side, then cut out the 1/2 deep slots with a table saw, one kerf-width at a time. I attached each one with a single, 5 1/2” bolt from the top, then sealed up the hole with 1/2” dowels glued into place.

The columns are boxes made of Hardi-plank. I cut the tapered sides using a portable saw attached to a guide plate slotted into this giant (like 7 foot long) clamp guide that I bought at Peachtree Woodworking. This enabled perfect, long straight edge cuts with no drift or edge issues. I nailed 2X2 inch cleats along the edges of the Hardiplank so I could assemble the columns. Since the columns are not protected from the elements, I filled all seams and nail holes with automotive repair epoxy (bondo), and sanded them smooth.

Inside the columns, the structural strength is provided by pressure treated 6X6 lumber, mounted onto Simpson standoffs to keep the water at bay. I cut tenons into the tops of each PT column that fit into mortises in the beam, for a rock solid connection between the beam and the columns.

For additional water protection, the bottom of the Hardiplank is about 1” above the stone porch floor. The trim on the bottom of the columns fills that gap, and is made of PVC, so it won’t absorb or take up any water. Even that trim floats 1/4” or so above the deck, so that water can flow underneath it.

All the other trim is PVC too, except for the capital piece (very top of columns), which is cypress. The columns have one coat of Kilz oil exterior primer, and three coats of latex paint.

Finally, there are two low-voltage footlights, one in each column.

Wood cost was about $500. With hardware, lights, Hardi-plank, etc., about $800 all in.

Thanks for your comments! To Jeff NJ, I did seal the tops of the columns, but I didn’t install anything to shed or drain the water (channels or drain holes). The tops gets direct sun, so water doesn’t stand for long.